<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container{
            width: 1240px;
            height:500px;
            position: relative;
        }
        .container img{
            width: 1240px;
            height: 500px;
            display: block;
        }
        .sidebar{
            position: absolute;
            top:0;
            left:0;
            width:200px;
            height: 500px;
            background-color: rgba(0,0,0,.5);
        }
        .btn-left{
            width: 50px;
            height: 50px;
            background-color: red;

            position: absolute;
            top:225px;
            left:200px;

        }
        .btn-right{
            width: 50px;
            height: 50px;
            background-color: red;

            position: absolute;
            top:225px;
            right:0px;

        }
        .direct{
            position: absolute;
            width: 180px;
            height:40px;
            background-color: red;
            bottom: 20px;
            left: 630px;
        }
    </style>
</head>
<body>
    <h1>定位案例</h1>
    <div class="container">
        <img src="./imgs/bg.jpg" alt="">
        <div class="sidebar">
            xx
        </div>
        <div class="btn-left">left</div>
        <div class="btn-right">right</div>
        <div class="direct">。。。</div>
    </div>

</body>
</html>